Check
Cloudflare or a CDN is blocking AI crawlers
Bot Fight Mode, a managed rule or a WAF rule is refusing AI user agents before the request reaches your application. Your own logs may show nothing at all.
How to confirm it
Run this against your own domain:
curl -sS -A "ClaudeBot/1.0" -o /dev/null -w "%{http_code} %{size_download}\n" https://example.com/
How to fix it
Add a WAF skip rule for verified AI agents, keep the challenge off for them, and confirm from the CDN's own analytics that the requests are now reaching the origin.
Where it fits
This is a symptom of a failed check — here it points at A1. The failure it belongs to is only one of fifteen; the full list is in the standard, and the fix order that avoids redoing work is in the repair guide.